U.S. patent application number 14/442298 was filed with the patent office on 2016-09-29 for high pressure pump.
This patent application is currently assigned to SAFRAN POWER UK LTD.. The applicant listed for this patent is SAFRAN POWER UK LTD.. Invention is credited to Stephen Mark HEARN, Darren Christopher HOWARD.
Application Number | 20160281713 14/442298 |
Document ID | / |
Family ID | 47521435 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160281713 |
Kind Code |
A1 |
HOWARD; Darren Christopher ;
et al. |
September 29, 2016 |
HIGH PRESSURE PUMP
Abstract
A high pressure pump including a pump body, a pump housing
within which at least part of the pump body is located, a gallery
defined between the pump body and the pump housing, the pump body
having a pump outlet which communicates with the gallery, and the
pump housing having an outlet port which communicates with the
gallery, and a filler located within the gallery, the filler being
located at least in the part of the gallery most remote from the
pump outlet.
Inventors: |
HOWARD; Darren Christopher;
(Buckinghamshire, GB) ; HEARN; Stephen Mark;
(Hertfordshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAFRAN POWER UK LTD. |
Buckinghamshire |
|
GB |
|
|
Assignee: |
SAFRAN POWER UK LTD.
Buckinghamshire
GB
|
Family ID: |
47521435 |
Appl. No.: |
14/442298 |
Filed: |
November 20, 2013 |
PCT Filed: |
November 20, 2013 |
PCT NO: |
PCT/EP2013/074293 |
371 Date: |
May 12, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 11/006 20130101;
F04C 15/0049 20130101; F04C 15/06 20130101; F04C 11/005 20130101;
F04C 2/10 20130101; F04C 15/0007 20130101; F04C 2210/206
20130101 |
International
Class: |
F04C 15/06 20060101
F04C015/06; F04C 11/00 20060101 F04C011/00; F04C 15/00 20060101
F04C015/00; F04C 2/10 20060101 F04C002/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 20, 2012 |
GB |
1220852.6 |
Claims
1-15. (canceled)
16. A high pressure pump comprising: a pump body; a pump housing
within which at least part of the pump body is located; a gallery
defined between the pump body and the pump housing, the pump body
having a pump outlet which communicates with the gallery, and the
pump housing having an outlet port which communicates with the
gallery; and a filler located within the gallery, the filler being
located at least in the part of the gallery most remote from the
pump outlet.
17. The pump of claim 16, wherein the gallery is of annular
form.
18. The pump of claim 17, wherein the filler extends about at least
half of the circumferential length of the gallery.
19. The pump of claim 18, wherein the filler extends about at least
three quarters of the gallery.
20. The pump of claim 16, wherein a cross-sectional shape of the
filler conforms with that of the gallery.
21. The pump of claim 16, wherein the filler substantially fills at
least part of the gallery furthest from the pump outlet.
22. The pump of claim 16, wherein the filler is of an elastomeric
material.
23. The pump of claim 16, wherein the filler is of molded
fluorocarbon form.
24. The pump of claim 16, wherein the filler forms an interference
fit in the gallery.
25. The pump of claim 16, further comprising locator means to
resist movement of the filler within the gallery.
26. The pump of claim 25, wherein the locator means comprises
locator pins provided in the gallery and arranged to abut ends of
the filler to resist movement of the filler.
27. The pump of claim 16, wherein the filler incorporates an
integral projection configured to be received within a
corresponding recess formed in the pump body and/or pump housing to
resist movement of the filler.
28. The pump of claim 16, wherein adjacent the gallery, the pump
body and pump housing are sealed to one another.
29. The pump of claim 28, wherein adjacent the gallery, the pump
body and pump housing are sealed to one another by o-ring
seals.
30. The pump of claim 16, further comprising at least one gerotor
pump.
Description
[0001] This invention relates to a high pressure pump, and in
particular to a high pressure pump for use in the supply of oil to
a generator.
[0002] EP1486675 describes an electrical generator for use in
aerospace applications. In order to provide lubrication for the
bearings of the generator, and to provide cooling for the
generator, a high pressure oil pump is provided. The high pressure
pump takes the form of a two stage pump including a first stage in
the form of a centrifugal pump whereby oil is drawn from a
reservoir and delivered to a second stage in the form of a gerotor
pump. The gerotor pump delivers oil under high pressure to a
manifold of the generator from which it is supplied for the
aforementioned cooling and lubrication purposes.
[0003] In practice, the second stage may comprise two gerotor pumps
arranged in series with one another so as to raise the oil pressure
still further.
[0004] The pump includes a pump body located within a pump housing.
The pump body and/or housing are shaped so as to define,
therebetween, an annular gallery with which the outlet of the
second stage communicates, the annular gallery communicating with
an outlet port provided in the pump housing and from which the oil
is delivered under high pressure to the manifold.
[0005] The nature of a gerotor pump is such that pressure pulses
develop at the outlet thereof. It has been found that erosion
occurs in the part of the annular gallery furthest from the outlet
of the second stage of the pump. This erosion can result in damage
to the pump body and/or the pump housing, and/or to seals located
therebetween at this point, resulting in the escape of oil
therefrom. As a result, the rate of delivery of oil by the pump,
and the pressure at which the oil is delivered may reduce.
Reductions in the rate of oil delivery or pressure at which the oil
is delivered may result in insufficient cooling of the generator
and/or in insufficient lubrication of the bearings thereof.
Clearly, this is undesirable as damage to the generator may occur.
Furthermore, as the generator will typically incorporate sensors to
detect the oil pressure and the temperature of the generator, and a
control system which controls the operation of the generator using
the outputs of such sensors, the control system may cause the
generator to be shut down as a result of insufficient oil being
delivered.
[0006] It is an object of the invention to provide a high pressure
pump in which at least some of the disadvantages set out
hereinbefore are overcome or are of reduce effect.
[0007] According to the present invention there is provided a high
pressure pump comprising a pump body, a pump housing within which
at least part of the pump body is located, a gallery defined
between the pump body and the pump housing, the pump body having a
pump outlet which communicates with the gallery, and the pump
housing having an outlet port which communicates with the gallery,
and a filler located within the gallery, the filler being located
at least in the part of the gallery most remote from the pump
outlet.
[0008] The gallery is conveniently of annular form. The filler
preferably extends about at least half of the circumferential
length of the gallery. Conveniently, it extends about at least
three quarters of the gallery. The cross-sectional shape of the
filler conveniently conforms with that of the gallery.
Consequently, the filler substantially fills at least the part of
the gallery furthest from the pump outlet.
[0009] The filler is conveniently of an elastomeric material. For
example, it may be of moulded fluorocarbon form. The filler
preferably forms an interference fit in the gallery.
[0010] Locator means are preferably provided to resist movement of
the filler within the gallery. The locator means may comprises
locator pins provided in the gallery and arranged to abut the ends
of the filler to resist movement of the filler. The filler may
incorporate an integral projection adapted to be received within a
corresponding recess formed in the pump body and/or pump housing to
resist movement of the filler.
[0011] Adjacent the gallery, the pump body and pump housing are
preferably sealed to one another, for example by the use of o-ring
seals.
[0012] The high pressure pump conveniently incorporates at least
one gerotor pump.
[0013] It is thought that in the known high pressure pump, the
erosion and wear which occurs results from cavitation erosion
caused by pressure spikes or ripples being transmitted from the
pump outlet around the gallery in both directions. By providing the
filler, the contact with and/or the quantity of oil within the part
of the gallery most remote from the pump outlet and so most
susceptible to such cavitation erosion is reduced, and as a
consequence, the occurrence of such erosion is reduced.
Furthermore, by the use of an elastomeric material for the filler,
it may be possible to partially absorb the pressure spikes and so
reduce the occurrence of cavitation erosion.
[0014] The invention will further be described, by way of example,
with reference to the accompanying drawings, in which:
[0015] FIG. 1 is a sectional view illustrating a high pressure pump
in accordance with an embodiment of the invention;
[0016] FIG. 2 is a diagram illustrating part of the pump of FIG.
1;
[0017] FIG. 3 is a perspective view illustrating part of the pump
of FIG. 1;
[0018] FIG. 4 is a view illustrating another part of the pump;
and
[0019] FIG. 5 is a view illustrating a modification.
[0020] Referring firstly to FIGS. 1 and 2, a high pressure pump is
illustrated, the pump being intended for use in the supply of oil
to a generator for lubrication and cooling purposes. Whilst
described in connection with a pump for such use, it will be
appreciated that the invention is not restricted in this regard and
may be used in other applications.
[0021] The pump comprises a pump body 10 of generally stepped
cylindrical shape and through which a drive shaft 12 extends. The
drive shaft 12 carries, at one end thereof, the rotor 14 of a
centrifugal pump 16, operation of the centrifugal pump 16 serving
to draw oil from a sump (not shown) along an inlet pipe 18,
delivering the oil to a sump 20 located within a pump housing 22.
The pump body 10 is located, at least in part, within the pump
housing 22 and is secured thereto against movement, in use.
[0022] The pump body 10 houses a gerotor type pump 24 having a pump
inlet 25 communicating, in use, with the sump 20, and a pump outlet
26, the gerotor type pump 24 serving to deliver oil supplied
thereto, from the sump 20, to the pump outlet 26 at high
pressure.
[0023] The pump body 10 defines, on its outer periphery, and
annular recess 28 which, together with the pump housing 22, forms
an annular gallery 30. As shown in FIG. 2, the pump outlet 26
communicates with the annular gallery 30, thus the output from the
gerotor pump 24 is supplied to the annular gallery 30.
[0024] As shown in FIG. 1, the pump housing 22 includes an outlet
port 32 which communicates, via an outlet passage 34, with the
annular gallery 30. Accordingly, operation of the gerotor pump
serves to deliver oil at high pressure to the outlet port 32 from
where it may be delivered via a manifold or the like, if desired,
to an associated electrical generator for lubrication and/or
cooling purposes.
[0025] The pump outlet 26 is substantially aligned with the point
at which the outlet passage 34 opens into the annular gallery 30,
in use.
[0026] Adjacent the annular gallery 30, the pump body 10 is
provided with annular grooves in which o-ring seals 36, 38 are
provided, the o-ring seals bearing against the pump housing 22 to
form seals therewith and so resist the escape of oil from the
annular gallery 30 either back towards the sump 20 or out of the
pump and into the interior of the generator in an uncontrolled
manner.
[0027] A gerotor pump produces pressure ripples or spikes at its
outlet, in use. As mentioned hereinbefore, it has been found that
increased levels of wear are experienced in the part of the annular
gallery 30 furthest from the pump outlet 26. This wear can result
in damage to the pump housing and/or body with which the seals
engage and/or in damage to the o-ring seals 36, 38 at or close to
this location, reducing the effectiveness of the seals. The damage
to the seals or sealing effect can result in the escape of oil from
the pump, or in the return of oil to the sump 20, reducing the rate
at which oil is delivered to the outlet port 32 and/or the pressure
at which oil is delivered. This can give rise to increased wear
and/or overheating of the generator, or may result in the generator
being switched off by its associated controller as a result of
insufficient oil pressure being detected. It is thought that the
increased levels of wear arising at the part of the annular gallery
most remote from the pump outlet 26 are caused by cavitation
erosion. It is thought that the pressure ripples or spikes are
transmitted in both directions around the annular gallery from the
pump outlet 26, and so the pressure fluctuations experienced at the
point furthest from the pump outlet 26 are significantly greater
than those experienced elsewhere. The range of pressures
experienced at this location are approximately twice those
experienced elsewhere. Cavitation erosion is thus thought to be
most significant at the point most remote from the pump outlet 26,
and this is thought to be the cause of the accelerated wear at this
location.
[0028] In accordance with this embodiment of the invention, as
shown in FIGS. 1 and 3, a filler element 40 is located within the
annular gallery 30. The filler element 40 cannot extend about the
entire circumference of the annular gallery 30 as this would
prevent or restrict the flow of oil between the pump outlet 26 and
the outlet passage 34. Rather, therefore, the filler element 40
extends around only part of the circumferential length of the
gallery 30. The part of the gallery 30 in which the filler element
40 is located includes the part thereof furthest from the pump
outlet 26. However, the filler element 40 is conveniently long
enough that it extends about at least half of the circumferential
length of the annular gallery 30. Preferably, it extends about
considerably more of the annular gallery 30 than this. By way of
example, in the illustrated embodiment, the filler element 40
extends around about three quarters of the annular gallery 30.
[0029] The dimensions of the filler element 40 are conveniently
such that the filler element 40 substantially fills the relevant
parts of the annular gallery 30, leaving little if any space
available to accommodate oil. Preferably the filler element 40 is
an interference fit within the annular gallery 30.
[0030] It is thought that by substantially filling the relevant
parts of the annular gallery 30 with the filler element 40, contact
between the pressurised oil and the housing 22, and/or the
transmission of pressure ripples or spikes to the part of the
annular gallery 30 most remote from the pump outlet 26, is reduced
or avoided, thus the occurrence of cavitation erosion at that
location is avoided or significantly reduced. By avoiding such
cavitation erosion, damage in the region of the o-ring seals 36, 38
and the parts providing support therefore is reduced and so the
output of the pump is maintained.
[0031] The filler element 40 is preferably of an elastomeric
material. As a result, not only does the filler element 40 serves
to reduce the passage of oil to the part of the annular gallery 30
most remote from the pump outlet 26, but also compression and
subsequent relaxation of the elastomeric material may serve to
partially absorb the pressure spikes, further reducing the impact
of cavitation erosion at the part of the annular gallery 30 most
remote from the pump outlet 26. By way of example, the filler
element 40 may be of moulded fluorocarbon form.
[0032] As the filler element 40 does not extend around the entirety
of the annular gallery 30, it is important for it to be held
against movement relative to the pump housing 22 and/or pump body
10 in order to ensure that the filler element 40 does not block the
pump outlet 26 or outlet passage 34. In some circumstances, this
may be achieved simply by virtue of the frictional forces
experienced between the filler element 40 and the walls defining
the annular gallery 30. However, it is desirable to provide
location means serving to positively resist movement of the filler
element 40.
[0033] As shown in FIG. 3, the location means may comprise a
projection or boss 42 integrally formed with the filler element 40
and arranged to be received within a corresponding recess 44 formed
in the pump housing 22, as shown in FIG. 4.
[0034] Alternatively, the boss 42 may be located and arranged to be
received within a corresponding recess formed in the pump body 10.
In each case, the boss 42 and recess 44 together serve to resist
movement of the filler element 40.
[0035] An alternative location means is shown in FIG. 5. In this
arrangement, locating pins 46 are fitted to the pump housing 22 or
pump body 10, within the part forming the annular gallery 30, the
pins 46 being arranged to abut the ends of the filler element 40,
and so resist movement thereof.
[0036] It will be appreciated that these two forms of location
means could be used in combination with one another, if
desired.
[0037] Regardless as to the type of location means used, resisting
movement of the filler element 40 ensures that the pump outlet 26
and outlet passage 34 remain unobscured and in communication with
one another.
[0038] It is thought that the invention may be applied to a number
of known pump designs, and may be retrofitted to existing pumps as
well as incorporated into new pumps. Modifications to existing pump
components to allow the incorporation of the invention are
minimal.
[0039] Whilst specific embodiments of the invention are described
herein, it will be appreciated that a wide range of modifications
and alterations may be made thereto without departing from the
scope of the invention.
* * * * *